SPR ISH upper build

AR/M4 AR General Discussion
1

Hey all

I am planning on building an SPR inspired upper reciever. This will be my 4th AR build but the first one that I want more than just a fun gun to shoot at the range. My intended use is varmint hunting, and target shooting. I’d like an upper capable of reaching out to 500+ yards and being more accurate than I am capable of being at 100 yards. 1.5"-2" groups at 100 yards or better.

Parts list
BCM upper reciever
BCM auto BCG
BCM SS410 SAM-R 20 inch barrel (any advantage for 20 over the 18, is this a solid barrel or are there better options for around the same price?)
TROY battle rail 15 inch (any other options I should consider?)
Magpul mbus
generic A2 flash hidder or a cheap ish muzzle break haven’t really done alot of looking here yet.
Miscellaneous parts

Optics
I was thinking either a vortex offering or a nikon offering. 3-10 ish power scope. I really need some help in this area, I’m not looking to spend $1000s either. My goal would be to be under $400.

So what do you all think of the parts list will I be able to get the performance I am looking for from this upper?

Any tips or tricks for the actual assembly process that really matter when your trying to get the best pssible accuracy?

Thanks for your help.

Nick

2

If you plan on running a bipod you might consider a more rigid rail than the troy (my vote would be a Geissele).

3

If you are going with 20", Id suggest this barrel, same profile as the Army SDM barrel, but with a finish that a file wont scratch.

Superior Barrels 20" SDM Barrel

4

I’m not to concerned about scratching as the rifle will be painted. Also I was thinking the troy due to its lightness but I will be running a bipod with the set up.

5

Some potential optics

Vortex Diamondback HP 3-12x42mm

Leupold VX-1 3-9x40mm

Leupold VX-2 3-9x40mm

Nikon p 223 3-9x40mm

6

The throat and gas port are equally resistant to wear from heat and friction, you cannot shoot this barrel out.

7

I would look at a Centurion Arms rail or the Geissele MKII SMR.

8

That’s a bold claim.

9

I did some more reading and the troy rail is probably out now. I really like the look of the geissele rails…

Also wonder if the 13 inch rail will look short on the 20 inch barrel…

What do you mean that you cannot shoot this barrel out? I was under the impression that SS barrels where good for 5000 rounds of 556 or so?

Nick

10

It’s melonited or whatever they call their version of it. DD, LWRC, Adams Arms, S&W, and a few other companies do it to their barrels to increase corrosion resistance and increase the hardness of their barrels and thus resistance to wear.

It’s not a gimmick by any means, but the claim that you “cannot” shoot them out is ridiculous.

I personally would go for a 16" AR with a light profile instead of a 20" with a heavier profile.

11

I already have a decent light 16 inch rifle. I want something longer I’m still not sold on the 18 vs 20 inch length.

12

Well a 16" can reach out to 500. There are only incremental gains from 16 to 18 and even less incremental gains from 18 to 20.

If you’re building a target shooting rifle whose only use is while on the bench or prone at a range… get the longest and heaviest barrel you can get.

If you only need 1.5-2" MOA precision, I’d go back to a lighter weight 16" barrel, especially if you’re planning on actually carrying it places.

13

I started ordering parts today excited to start getting things put together. I’m going with the 20inch mobility isn’t a concern of mine with this upper. And I want the best accuracy and ballistics that I can get at 500+ yards. I haven’t bought sights, optics, rail system, or optics mounts yet.

14

You may want to go with a non-threaded barrel, it can often help a little with regards to accuracy. Probably not a problem if you’re not looking to get every last mm off your group though.